It is known that a tire tread surface can be scanned with a flat light beam to form an image of a strip-shaped profile of the tread surface and record it with a camera. An example of sensors that can be used to scan a tire tread surface is described in U.S. Pat. No. 6,535,281, titled “METHOD AND APPARATUS FOR OPTICALLY SCANNING A VEHICLE WHEEL,” the entire disclosure of which is incorporated herein by reference. The sensor device includes a light source for emitting a light beam, and a light sensitive receiver for sensing lights. The light source and the receiver move synchronously. The surface of a motor vehicle wheel is scanned by a light beam emitted from the light source. The reflected beam is received by the light-sensitive receiver. The spacing of the scanned location of the wheel with respect to a reference location is determined based on the directions of the emitted beam and the reflected beam.
This disclosure describes methods and apparatus for comprehensively ascertaining the nature of the pneumatic tire of a motor vehicle wheel with improved efficiency. A vehicle wheel under test is mounted rotatably to a measuring shaft of a wheel balancing machine. At least one light beam, such as a laser beam, is directed from a light source disposed at a given position on to the surface of the pneumatic tire. The at least one light beam is reflected from the surface of the pneumatic tire and received by a light-sensitive receiver disposed at a given position. A sensor device includes the light source and the light-sensitive receiver may be used to scan the tread surface of the pneumatic tire. Dimensions and positions of the pneumatic tire or constituent parts of the pneumatic tire are ascertained based on the directions of the at least one emitted light beam and the reflected light beam.
To scan the two side walls of a tire and the tread thereof, it is possible to use a single sensor device that has the light source and the receiver on a common carrier. Alternatively, three sensor devices, each having the light source and the receiver on a common carrier, may be provided to each different surfaces of the tire. For example, a sensor device may be associated with the inside tire side wall, the outside tire side wall, and the tread surface, respectively.
A plurality of surface locations and/or spots on the pneumatic tire is scanned in succession when the tire is rotated. Dimensions and positions of the pneumatic tire or constituent parts of the pneumatic tire are ascertained based on the directions of the emitted light beam and the reflected light beam. Based on the dimensions and positions of the pneumatic tire or constituent parts of the pneumatic tire, it is possible to detect irregular wear of the tire or the tire profile depth at the tread surface as well as unacceptable conicity of the tread surface. Based on the profile depth, it is possible to ascertain the probable period of use of the tire, up to a required tire change. In addition, it is possible to ascertain irregular tire wear such as abrasion tracks extending crosswise or flat abrasion tracks on parts of the tread surface as well as tire shoulder wear and irregular tire shoulders and the like. In addition, scanning the side walls of the tire makes it possible to detect indentations or bulges in those parts of the tire. It is also possible to detect an irregular fit of the tire in the rim base.
Additional aspects and advantages of the present disclosure will become readily apparent to those skilled in this art from the following detailed description, wherein only exemplary embodiments of the present disclosure is shown and described, simply by way of illustration of the best mode contemplated for carrying out the present disclosure. As will be realized, the present disclosure is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.